Last time I put my big block together I used a Comp cam nylon thrust button. It was about .030 to long so I removed .030 from the cam side. The button fit tight in the gear when installed. I was going to reuse the button when I put it together this time but it doesn't fit tight in the gear. The button is about .004 smaller in diameter then it was originally. It looks like instead of turning with the gear, it turned in the gear. It's button is still exactly the same length as it was when I put it together last time. There is only a small contact point on the front cover. The front cover is an Edelbrock aluminum. Solid roller cam. The engine only had about 500 miles on it. What should I do this time?